Modeling of a fracturing model in Excel

This is taken from Turcotte's book on fractals
in the geoscience. The simple rule is that you start with a cube
and break it into 8 blocks. Of those 8, 2 diagonal blocks go on
to survive and stay intact, while the remaining 6 fracture again
to each create 8 more blocks. This process is repeated again and
again. The fracture geometry is fractal. A plot of particle size
versus the number of particles with that size shows a nice log-log
linear relationship. A similar relationship is found in naturally
fragmented material (see Turcotte.)